Begell House Inc.International Journal of Energetic Materials and Chemical PropulsionIJEMCP2150-766X1142012LASER IGNITION PROPERTIES OF COMPOSITE NANOMETRIC ENERGETIC MATERIALS293-298Shawn C.StacyDepartment of Mechanical Engineering, Texas Tech University, Lubbock, Texas, USAMichelle L.PantoyaDepartment of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409 USALaser ignition delay experiments were conducted in order to better understand the effects of thermal and chemical properties on ignition mechanisms for energetic materials. A Nd:YAG laser (10 ms, ~2 J, 3-mm beam diameter, 1064-nm wavelength) was used to heat the top surface of a reactive material powder, and ignition delay was calculated as the difference between first light of the laser's flash lamp and the sample. In the compositions tested, nanometric aluminum (Al) was used as the fuel and combined stoichiometrically with an oxidizer [copper oxide (CuO), iodine pentoxide (I2O5), polytetrafluoroethylene (C2F4), molybdenum trioxide (MoO3), tungsten trioxide (WO3), or iron oxide (Fe2O3)]. Results show that ignition delays for asymmetrical heating are strongly affected by thermal properties. A key result is that ignition delay was found to be inversely proportional to the molar heat capacity of the oxidizer.INNOVATIVE METAL FUELS FOR SOLID ROCKET PROPULSION299-322StefanoDossiSPLab, Space Propulsion Laboratory, Aerospace Engineering Department, Politecnico di Milano, 34 via la Masa, 20156 Milan, ItalyAliceReinaSPLab, Space Propulsion Laboratory, Aerospace Engineering Department, Politecnico di Milano, 34 via la Masa, 20156 Milan, ItalyFilippoMaggiSPLab, Space Propulsion Laboratory, Aerospace Engineering Department, Politecnico di Milano, 34 via la Masa, 20156 Milan, ItalyLuigi T. De LucaSpace Propulsion Laboratory (SPLab), Department of Aerospace Science
and Technology, Politecnico di Milano, I-20156 Milan, ItalyTwo groups of innovative metal fuels are addressed in this paper. Three nanometric powders nominally ranging from 50 to 100 nm were contrasted to three micrometric activated aluminum powders, in terms of active metal content, specific surface area, scanning electron microscopy imaging, laser granulometry, and ignition properties in air. Both nanosized and activated aluminum powders featured augmented reactivity as well as a higher fraction of oxidized metal with respect to standard micrometric aluminum. All metal powders were also used as fuels for a series of composite AP (ammonium perchlorate)/Hydroxyl Terminated Polybutadiene (HTPB)/metal propellants, in either total or partial replacement of micrometric aluminum (baseline). Burning rates were contrasted to powder properties (mainly, specific surface area of the fuel), discussing the correlation between these parameters. A specific analysis on particle shape factor was also conducted on three micrometric powders. In this regard, a framework for the characterization of particle roundness was implemented and used for the cross comparison among several lots of powders for propulsion application (space-grade) as well as painting industry (industrial-grade), providing a statistical management of particle shape features.GLYCIDYL AZIDE POLYMER−COMBUSTION MECHANISM AND ITS APPLICATION TO HYBRID ROCKET MOTORS323-351KeiichiHoriInstitute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-Ku, Sagamihara, Kanagawa 252-5210, JapanMakihitoNishiokaUniversity of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki, 305-8577, JapanA one-dimensional three-phase mode combustion model of GAP [glycidyl azide polymer, poly (3-nitratoethyl-3-methyloxetane)] was developed. Combustion residues; soot (black color), high-viscosity residue, and yellow powder which was only observed at high pressures were analyzed by means of scanning electron microscopy and Fourier transform infrared, and the mass balance was also measured. Modifications of the combustion model were made taking these residue analysis results into account as the "blow off mechanism," and the simulated temperature profiles and linear burning rates coincide well with the experimental data adjusting kinetic parameters. Hybrid rockets using GAP as a solid fuel have been studied. The linear burning rate spectrum of GAP was widened with the dilution by polyethylene glycol (PEG), and basically, self-combustible mixtures are used for the gas hybrid rocket motor, and non-self-combustible mixtures for the traditional hybrid motor. Thrust control, quench, and re-ignition were successfully performed using a gas hybrid system, and simultaneous measurements of the surface regression rate and temperature of the traditional hybrid motor have been conducted using an ultrasonic technique with a special combustion chamber. GAP, mixtures of GAP and PEG, PEG and hydroxyl-terminated polybutadiene fuels have been tested and experimental results are summarized and discussed in this paper.OXIDATION, IGNITION AND COMBUSTION OF AL-HYDROCARBON COMPOSITE REACTIVE POWDERS353-373ShashaZhangNew Jersey Institute of Technology, Newark, NJ 07029 USA; Key Laboratory of Hydraulic Machinery Transients, MOE, Wuhan University, Wuhan, 430072, China; School of Power and Mechanical Engineering, Wuhan University, Wuhan, Hubei 430072, China MirkoSchoenitzNew Jersey Institute of Technology, Newark, New Jersey 07102, USAEdward L.DreizinNew Jersey Institute of Technology, Newark, New Jersey 07102, USA; Tomsk State University, Tomsk, 634050, RussiaMetal fuel additives are used in advanced explosive formulations to achieve higher combustion temperatures and longer pressure pulses. Cryomilling is used to prepare Al-based reactive composites to replace pure Al as a fuel additive in explosives for multiple applications. In this project, Al-paraffin wax and Al-polyethylene composite materials were prepared and characterized. The prepared powders were initially evaluated using thermogravimetric analysis, scanning electron microscopy, and X-ray diffraction. Ignition temperatures of the prepared materials were determined at heating rates varied in the range of 2000-23000 K/s using an electrically heated filament. Materials were burned as individual particles and as aerosolized clouds. Ignition temperatures were significantly lower for all composite materials compared to pure Al. Single particle burn times were longer and combustion temperatures were comparable to those of pure Al powders. Combustion dynamics of the composite material particles was affected by the hydrocarbon additives retained in the material after its ignition despite the very high combustion temperatures. In aerosol combustion tests, the pressure for Al-hydrocarbon composites was negatively affected by strong agglomeration of the partially burned particles.EFFECT OF BALLISTIC MODIFIERS ON THE BURN RATE OF EXTRUDED COMPOSITE PROPELLANT FORMULATIONS BASED ON THERMOPLASTIC ELASTOMERIC BINDER375-388K. S. MulageHigh Energy Materials Research Laboratory, Sutarwadi, Pune-411 021, IndiaA. K. MishraHigh Energy Materials Research Laboratory, Sutarwadi, Pune-411 021, IndiaR. N. PatkarHigh Energy Materials Research Laboratory, Sutarwadi, Pune-411 021, IndiaS. H. KharatHigh Energy Materials Research Laboratory, Sutarwadi, Pune-411 021, IndiaPawan KumarKhannaDefence Institute of Advanced Technology, Pune, 411025, IndiaSeema DilipKakadeHigh Energy Materials Research Laboratory, Pune, 411021, IndiaThe effect of ballistic modifiers on the burn rate of extruded composite propellant (ECP) formulations primarily based on ammonium perchlorate (AP) as oxidizer, aluminum (Al) as metallic fuel, and thermoplastic polyurethane, viz., Irostic® as binder, has been investigated. The ballistic modifiers, viz., iron oxide (Fe2O3), copper chromite (CuCr2O4), and strontium carbonate (SrCO3), were studied in the concentration varying from 0.2 to 1.0 part above 100 parts of base composition. The results obtained reveal that the burn rate increases with increase in the concentration of Fe2O3 and CuCr2O4. Maximum burn rate enhancement is observed with 1 part of Fe2O3, which is of the order of 130%. The results are discussed in detail in the light of thermal decomposition data generated on polymer and propellant compositions using ballistic modifiers.